화학공학소재연구정보센터
Journal of Hazardous Materials, Vol.175, No.1-3, 614-621, 2010
Mechanism of the anodic oxidation of 4-chloro-3-methyl phenol in aqueous solution using Ti/SnO2-Sb/PbO2 electrodes
Electrochemical oxidation of 4-chloro-3-methyl phenol (CMP) was examined using Ti/SnO2-Sb/PbO2 anodes. The physicochemical properties of the electrodes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The degradation was studied by monitoring the total organic carbon (TOC) removal of CMP, and variation of the concentration of intermediates by high-performance liquid chromatography (HPLC), ion chromatography (IC) and gas chromatography/mass spectrometry (CC/MS). The mineralization of CMP is confirmed to be controlled by mass transfer or by both chemical reaction and mass transfer. Hydroxyl radicals ((OH)-O-center dot) and active chlorine on the electrode surface had a dominant role in the electro-oxidation process. The chloride element in CMP was immediately driven away from parent substance by (OH)-O-center dot attack, and then accelerated the ring cleavage of methyl-p-benzoquinone, which was formed during the anodic oxidation of CMP. Ultimately, the chlorine of CMP was mainly transformed to hypochlorite and chloride ion in aqueous solution. Additionally, formic acid and acetic acid were relatively stable products that were not electro-oxidized efficiently in our experiments. The degradation pathway of CMP is proposed on the basis of these results. (C) 2009 Elsevier B.V. All rights reserved.